Generally, a torque sensor may detect a steering torque. For example, in a patent document, Japanese Patent No. 3551052 (patent document 1), the temperature characteristics of the torque signal are corrected based on a torque signal at the time of 20 degrees Celsius and the torque signal at the time of 80 degrees Celsius.
In the patent document 1, since neither an aged deterioration nor the accuracy variation (i.e., dimension errors) of the parts is taken into consideration, there is a possibility that the torque signal cannot be appropriately corrected.